1. Field of Invention
The invention relates to a technology of a paint filling apparatus that fills a paint into a paint cartridge for use in an electrostatic painting machine. More concretely, the invention relates to a technology for providing an economical and compact paint filling apparatus that is used to fill a paint cartridge with a paint of a color that is arbitrarily selected from a plurality of color paints.
2. Description of Related Art
Generally, the painting of bodies of motor vehicles and the like, due to its requirement for high painting quality, employs electrostatic painting machines that are excellent in the efficiency of adhesion of paint to painting surfaces, the smoothness of paint films after the painting process, etc. A widely known example of the electrostatic painting machines is a rotary atomizing head type painting machine. The rotary atomizing head type painting machine is equipped with a rotary atomizing head for atomizing a water base paint, a plurality of paint cartridges that are filled with paints of different colors, etc. To perform painting of an object to be painted, a paint cartridge filled with a paint of a designated color is selected. Then, the paint filled in the paint cartridge is jetted out via rotary atomizing heads, so that paint particles are atomized, and accomplish the painting. When the paint in the paint cartridge runs out, the paint cartridge is attached to a paint filling apparatus, and is thereby replenished with the paint. Thus, the rotary atomizing head type painting machine becomes able to carry out the painting again.
Incidentally, in the paint filling apparatus, it is necessary that a paint arbitrary selected from a plurality of paints of different colors be filled into the paint cartridge. If a connecting portion, between the paint filling apparatus and a paint cartridge (an opening for supplying paint into the paint cartridge) is provided only at one site regardless of the color of paint, the paint loss (an amount of paint that is not filled into the paint cartridge but is discarded) increases. That is, the connecting portion is linked in communication with a selected one of paint supply sources that are provided separately for each of colors of paints, via a supply channel whose intermediate portion has a plurality of branch channels. Therefore, in a construction in which the connecting portion is provided only at one site, when a “color changing operation” regarding the paint in the paint cartridge is performed, the entire region in the supply channel from the paint supply source to the connecting portion needs to be washed, and the amount of paint remaining in the supply channel is discarded as a paint loss.
In order to reduce the paint loss, there has been proposed a technology of a paint filling apparatus equipped with a plurality of paint supply portions that correspond to individual paint colors. An example of such an apparatus will be described with reference to FIGS. 5A and 5B.
A paint filling apparatus 201 is equipped with a plurality of manifold portions (paint supply portions) 202 for individual colors of paints. Besides, each manifold portion 202 is composed of a body portion 202A, an actuator 202B provided on a lower surface of the body portion 202A, etc. The body portion 202A is provided with a plurality of electromagnetic valves (a trigger valve 203, a paint valve 204, a cleaning liquid valve 205, an air valve 206, a waste liquid valve 207, an extrusion liquid supply valve 208, an extrusion liquid discharge valve 209, etc.). These valves 203, 204, . . . , 209 are connected to intermediate portions of supply channels connected to various supply sources, such as a paint tank, a cleaning liquid tank, an extrusion liquid tank, etc., and to an intermediate portion of a discharge channel connected to a waste liquid tank, etc.
In each common manifold portion 202, an upper surface of the body portion 202A has a support end surface 202a that is attachable to and detachable from a lower surface of a paint cartridge 10. Via the support end surface 202a, the paint cartridge 10 is firmly held on the upper surface of the body portion 202A. Besides, in each common manifold portion 202, the body portion 202A is movable in up-down directions by the actuator 202B.
When the paint cartridge 10 is to be filled with a paint, the paint cartridge 10 is firstly moved in the horizontal direction (the direction of an arrow X shown in FIG. 5A) by a conveyor device 254, and is conveyed to a position over a manifold portion 202 that deals with the selected color paint. When the paint cartridge reaches the position over the manifold portion 202, the body portion 202A of the manifold portion 202 is raised (in the direction of an arrow Y) via the actuator 202B, as shown in FIG. 5B. Then, via the support end surface 202a, the manifold portion 202 and the paint cartridge 10 are linked. After that, via the manifold portion 202, the paint starts to be filled into the paint cartridge 10.
Incidentally, as for paint filling apparatuses equipped with paint supply portions separately for each of colors of paints, various apparatuses other than the foregoing paint filling apparatus 201 have also been proposed (see Japanese Patent Application Publication No. 2000-176328 (JP-A-2000-176328), Japanese Patent Application Publication No. 2002-96002 (JP-A-2002-96002), and Japanese Patent Application Publication No. 4-200664 (JP-A-4-200664)).
According to the paint filling apparatus equipped with paint supply portions provided separately for each of colors of paints, it is possible to reduce the amount of paint discarded (the amount of paint loss) at the time of changing colors, in comparison with a paint filling apparatus that has only one site of connection with a paint cartridge as described above. In particular, according to the technologies shown in Japanese Patent Application Publication No. 2000-176328 (JP-A-2000-176328), Japanese Patent Application Publication No. 2002-96002 (JP-A-2002-96002) or Japanese Patent Application Publication No. 4-200664 (JP-A-4-200664), it is also possible to shorten the time required for the “color changing operation” as well as reduce the amount of paint discarded (paint loss) at the time of the “color changing operation”. However, as for the paint filling apparatus equipped with paint supply portions separately for individual colors of paints, since a plurality of common manifold portions are disposed separately for each of colors of paints, the paint filling apparatus as a whole becomes large in size, requiring a large space for installation. Besides, the overall cost for the paint filling apparatus is considerably high.